In △ABC,D is a point on BC such that ∠BAD = ∠ADC and ∠BAC = 77° and ∠c = 45°. What is the measures of ∠ADB?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 64°
In triangle ABC,
∠A + ∠B + ∠C = 180.
∠B = 180 - 77 - 45 = 58°.
By using the exterior angle property,
58 + a = 2a
a= 58
2a = 2 × 58 = 116
∠ADB = 180 - 116 ( linear pair)
∠ADB = 64°.